Device and Method of Sequence Detection for Frequency-Shift Keying

1. A device for determining an encoded data sequence as a determined data sequence, the encoded data sequence being encoded by an input signal frequency-modulated in accordance with a modulation rule, the encoded data sequence comprising a plurality of data elements, comprising: a filter unit for filtering the frequency-modulated input signal in order to acquire a first frequency-filtered channel signal and a second frequency-filtered channel signal, an evaluation unit configured to associate two channel-specific signal-to-noise distance values to each data sequence of a set of known data sequences, wherein the evaluation unit is configured to determine, for each data sequence of the set of known data sequences, a first channel-specific signal-to-noise distance value of the two channel-specific signal-to-noise distance values based on said data sequence and based on the first frequency-filtered channel signal, and wherein the evaluation unit is configured to associate said first channel-specific signal-to-noise distance value of the two-channel-specific distance values to said data sequence, wherein the evaluation unit is configured to determine, for each data sequence of the set of known data sequences, a second channel-specific signal-to-noise distance value of the two channel-specific signal-to-noise distance values based on said data sequence and based on the second frequency-filtered channel signal, and wherein the evaluation unit is configured to associate said second channel-specific signal-to-noise distance value of the two-channel-specific distance values to said data sequence, and wherein the evaluation unit is configured to select from the set of known data sequences a data sequence as the determined data sequence that has an associated channel-specific signal-to-noise distance value which is greater than another channel-specific signal-to-noise distance value associated to another one of the known data sequences.

2. The device in accordance with claim 1 , wherein the evaluation unit is configured to select one of the known data sequences as the determined data sequence that has an associated channel-specific signal-to-noise distance value which is greater than any other channel-specific signal-to-noise distance value associated to another one of the known data sequences of the set of known data sequences.

3. The device in accordance with claim 1 , wherein the filter unit for filtering the frequency-modulated input signal is configured to acquire the first frequency-filtered channel signal with a first center frequency and the second frequency-filtered channel signal with a second center frequency, wherein the filter unit is implemented such that a frequency portion of the first center frequency in the second frequency-filtered channel signal is zero or smaller than a frequency portion of the first center frequency in the first frequency-modulated channel signal, and wherein the filter unit is implemented such that a frequency portion of the second center frequency in the first frequency-filtered channel signal is zero or smaller than a frequency portion of the second center frequency in the second frequency-modulated channel signal.

4. The device in accordance with claim 1 , wherein the evaluation unit is configured to determine a set of channel-specific signal-to-noise distance values for each data sequence of the set of known data sequences, wherein said set of channel-specific signal-to-noise distance values comprises the first channel-specific signal-to-noise distance value of said data sequence of the set of known data sequences, and comprises the second channel-specific signal-to-noise distance value of said data sequence of the set of known data sequences, wherein the evaluation unit is configured to select from the set of channel-specific signal-to-noise distance values of each data sequence of the set of known data sequences, a greatest channel-specific signal-to-noise distance value as a data sequence signal-to-noise distance value of said data sequence of the set of known data sequences such that no other one of the channel-specific signal-to-noise distance values from the set of channel-specific signal-to-noise distance values of said data sequence of the set of known data sequences is greater, and wherein the evaluation unit is additionally configured to select that data sequence from the set of known data sequences as the determined data sequence such that there is no other data sequence from the set of known data sequences which has a signal-to-noise distance value being greater than the data sequence signal-to-noise distance value of the determined data sequence.

5. The device in accordance with claim 1 , wherein the evaluation unit is configured to determine a first signal power value for each data sequence of the set of known data sequences depending on said data sequence of the set of known data sequences and depending on the first frequency-filtered channel signal, wherein the evaluation unit is configured to determine the first channel-specific signal-to-noise distance value of each data sequence of the set of known data sequences depending on the first signal power value of said data sequence of the set of known data sequences, wherein the evaluation unit is configured to determine a second signal power value for each data sequence of the set of known data sequences depending on said data sequence of the set of known data sequences and depending on the second frequency-filtered channel signal, and wherein the evaluation unit is configured to determine the second channel-specific signal-to-noise distance value of each data sequence of the set of known data sequences depending on the second signal power value of said data sequence of the set of known data sequences.

6. The device in accordance with claim 5 , wherein the evaluation unit is configured to determine a first noise power value for each data sequence of the set of known data sequences depending on said data sequence of the set of known data sequences and depending on the first frequency-filtered channel signal, wherein the evaluation unit is configured to determine the first channel-specific signal-to-noise distance value of said data sequence of the set of known data sequences depending on the first signal power value of said data sequence of the set of known data sequences and depending on the first noise power value of said data sequence of the set of known data sequences such that the first channel-specific signal-to-noise distance value of said data sequence of the set of known data sequences indicates a size ratio of the first signal power value of said data sequence of the set of known data sequences relative to the first noise power value of said data sequence of the set of known data sequences, wherein the evaluation unit is configured to determine a second noise power value for each data sequence of the set of known data sequences depending on said data sequence of the set of known data sequences and depending on the second frequency-filtered channel signal, wherein the evaluation unit is configured to determine the second channel-specific signal-to-noise distance value of said data sequence of the set of known data sequences depending on the second signal power value of said data sequence of the set of known data sequences and depending on the second noise power value of said data sequence of the set of known data sequences such that the second channel-specific signal-to-noise distance value of said data sequence of the set of known data sequences indicates a size ratio of the second signal power value of said data sequence of the set of known data sequences relative to the second noise power value of said data sequence of the set of known data sequences.

7. The device in accordance with claim 6 , wherein the filter unit comprises a first filter element with a first pass region for filtering the frequency-modulated input signal in order to acquire the first frequency-filtered channel signal, wherein the evaluation unit is configured to determine the first signal power value of each data sequence of the set of known data sequences depending on a first group of first signal portions of the first channel signal, the first group of first signal portions comprising only such signal portions of the first channel signal for which said data sequence of the set of known data sequences indicates that a first data value of the encoded data sequence is encoded by these signal portions, in case the frequency-modulated input signal encodes said data sequence of the set of known data sequences, the first data value being encoded by signal portions which comprise frequency portions corresponding to a first encoding frequency, wherein the first filter element is implemented such that the first encoding frequency is in the pass region of the first filter element, and wherein the evaluation unit is configured to determine the first noise power value of each data sequence of the set of known data sequences depending on a third group of third signal portions of the first channel signal, the third group of third signal portions comprising only such signal portions of the first channel signal for which said data sequence of the set of known data sequences indicates that the first data value of the encoded data sequence is not encoded by these signal portions, in case the frequency-modulated input signal encodes said data sequence of the set of known data sequences.

8. The device in accordance with claim 7 , wherein the filter unit comprises a second filter element with a second pass region, different from the first pass region, for filtering the frequency-modulated input signal in order to acquire the second frequency-filtered channel signal, wherein the evaluation unit is configured to determine, the second signal power value of each known data sequence of the set of known data sequences depending on a second group of second signal portions of the second channel signal, the second group of second signal portions comprising only such signal portions of the second channel signal for which said data sequence of the set of known data sequences indicates that a second data value of the encoded data sequence is encoded by these signal portions, in case the frequency-modulated input signal encodes said data sequence of the set of known data sequences, the second data value being encoded by signal portions which comprise frequency portions corresponding to a second encoding frequency, wherein the second filter element is configured such that the second encoding frequency is in the pass region of the second filter element, the second filter element being implemented such that the first encoding frequency is not in the pass region of the second filter element, the first filter element being implemented such that the second encoding frequency is not in the pass region of the first filter element, and wherein the evaluation unit is configured to determine the second noise power value of each data sequence of the set of known data sequences depending on a fourth group of fourth signal portions of the second channel signal, the fourth group of fourth signal portions comprising only such signal portions of the second channel signal for which said data sequence of the set of known data sequences indicates that the second data value of the encoded data sequence is not encoded by these signal portions, in case the frequency-modulated input signal encodes said data sequence of the set of known data sequences.

9. The device in accordance with claim 6 , wherein the evaluation unit is configured to calculate the first channel-specific signal-to-noise distance value of each data sequence of the set of known data sequences by calculating: μ SN ⁢ ⁢ 0 - μ N ⁢ ⁢ 0 μ N ⁢ ⁢ 0 or by calculating: μ S ⁢ ⁢ N ⁢ ⁢ 0 μ N ⁢ ⁢ 0 wherein μ SN0 refers to the first signal power value of said data sequence of the set of known data sequences, and wherein μ N0 refers to the first noise power value of said data sequence of the set of known data sequences.

10. The device in accordance with claim 6 , wherein the evaluation unit is configured to calculate the second channel-specific signal-to-noise distance value of each data sequence of the set of known data sequences by calculating: μ SN ⁢ ⁢ 1 - μ N ⁢ ⁢ 1 μ N ⁢ ⁢ 1 or by calculating: μ S ⁢ ⁢ N ⁢ ⁢ 1 μ N ⁢ ⁢ 1 wherein μ SN1 refers to the second signal power value of said data sequence of the set of known data sequences, and wherein μ N1 refers to the second noise power value of said data sequence of the set of known data sequences.

11. The device in accordance with claim 6 , wherein the evaluation unit is configured to calculate the first signal power value of each data sequence of the set of known data sequences in accordance with the following formula: μ SN ⁢ ⁢ 0 = 1 K ⁢ ∑ j = 1 N s ⁢ ⁢  R ij - 1  ⁢ ∑ j = 1 N s ⁢ ⁢ ∑ n = ( j - 1 ) ⁢ K jK - 1 ⁢ ⁢ r 0 2 ⁡ [ n ] ⁢  R ij - 1  , wherein each data sequence of the set of known data sequences is a binary data sequence the data elements of which only take data values which are either 0 or 1, wherein each data sequence of the set of known data sequences comprises an equal number of N S data elements, wherein K corresponds to a number of samples having been determined by sampling for each first signal portion of a first group of first signal portions, wherein r 0 2 [n] refers to a squared n-th channel signal value of the first channel signal, and wherein R ij is a data value of a j-th data element of an i-th data sequence of the set of known data sequences, the i-th data sequence being said data sequence of the set of known data sequences for which the first signal power value is calculated.

12. The device in accordance with claim 11 , wherein the evaluation unit is configured to calculate the first noise power value of each data sequence of the set of known data sequences in accordance with the following formula: μ N ⁢ ⁢ 0 = 1 K ⁢ ∑ j = 1 N s ⁢ ⁢ R ij ⁢ ∑ j = 1 N s ⁢ ⁢ ∑ n = ( j - 1 ) ⁢ K jK - 1 ⁢ ⁢ r 0 2 ⁡ [ n ] ⁢ R ij , wherein K corresponds to a number of samples having been determined by sampling for each first signal portion of the first group of first signal portions and for each third signal portion of a third group of third signal portions.

13. The device in accordance with claim 12 , wherein the evaluation unit is configured to calculate the second signal power value of each data sequence of the set of known data sequences in accordance with the following formula: μ SN ⁢ ⁢ 1 = 1 K ⁢ ∑ j = 1 N s ⁢ ⁢ R ij ⁢ ∑ j = 1 N s ⁢ ⁢ ∑ n = ( j - 1 ) ⁢ K jK - 1 ⁢ ⁢ r 1 2 ⁡ [ n ] ⁢ R ij , and the second noise power value of each data sequence of the set of known data sequences in accordance with the following formula: μ N ⁢ ⁢ 1 = 1 K ⁢ ∑ j = 1 N s ⁢ ⁢  R ij - 1  ⁢ ∑ j = 1 N s ⁢ ⁢ ∑ n = ( j - 1 ) ⁢ K jK - 1 ⁢ ⁢ r 1 2 ⁡ [ n ] ⁢  R ij - 1  . wherein K corresponds to a number of samples having been determined by sampling for each first signal portion of the first group of first signal portions, for each second signal portion of a second group of second signal portions, for each third signal portion of the third group of third signal portions and for each fourth signal portion of a fourth group of fourth signal portions, and wherein r 1 2 [n] refers to a squared n-th channel signal value of the second channel signal.

14. The device in accordance with claim 1 , wherein the filter unit for filtering the frequency-modulated input signal is configured to acquire the first frequency-filtered channel signal, the second frequency-filtered channel signal and a third frequency-filtered channel signal, wherein the evaluation unit is configured to associate three channel-specific signal-to-noise distance values to each data sequence of the set of known data sequences, wherein the evaluation unit is configured to determine, for each known data sequence of a set of known data sequences, a third one of the three channel-specific signal-to-noise distance values associated to said data sequence of the set of known data sequences as a third channel-specific signal-to-noise distance value of said data sequence of the set of known data sequences based on said data sequence of the set of known data sequences and based on the third frequency-filtered channel signal, and wherein the evaluation unit is configured to select a data sequence from the set of known data sequences as the determined data sequence that has an associated channel-specific signal-to-noise distance value which is greater than another channel-specific signal-to-noise distance value associated to another data sequence of the set of known data sequences.

15. The device in accordance with claim 1 , wherein the filter unit for filtering the frequency-modulated input signal is configured to acquire the first frequency-filtered channel signal, the second frequency-filtered channel signal, a third frequency-filtered channel signal, and a fourth frequency-filtered channel signal, wherein the evaluation unit is configured to associate four channel-specific signal-to-noise distance values to each known data sequence of a set of known data sequences, wherein the evaluation unit is configured to determine, for each known data sequence of a set of known data sequences, a third one of the four channel-specific signal-to-noise distance values associated to said data sequence of the set of known data sequences as a third channel-specific signal-to-noise distance value of said data sequence of the set of known data sequences based on said data sequence of the set of known data sequences and based on the third frequency-filtered channel signal, wherein the evaluation unit is configured to determine, for each known data sequence of a set of known data sequences, a fourth one of the four channel-specific signal-to- noise distance values associated to said data sequence of the set of known data sequences as a fourth channel-specific signal-to-noise distance value of said data sequence of the set of known data sequences based on said data sequence of the set of known data sequences and based on the fourth frequency-filtered channel signal, wherein the evaluation unit is configured to select a data sequence from the set of known data sequences as the determined data sequence that has an associated channel-specific signal-to-noise distance value which is greater than another channel-specific signal-to-noise distance value associated to another data sequence of the set of known data sequences.

16. The device in accordance with claim 1 , the device being configured to determine an encoded data sequence encoded by the frequency-modulated input signal which is frequency-modulated by the modulation rule, the modulation rule being frequency-shift keying.

17. The device in accordance with claim 16 , the device being configured to determine an encoded data sequence encoded by the frequency-modulated input signal which is frequency-modulated by 4-FSK, 4-FSK being the modulation rule.

18. The device in accordance with claim 16 , the device being configured to determine an encoded data sequence encoded by the frequency-modulated input signal which is frequency-modulated by 8-FSK, 8-FSK being the modulation rule.

19. The device in accordance with claim 1 , wherein the evaluation unit comprises a first squaring unit for squaring the first frequency-filtered channel signal in order to acquire a first squared channel signal, wherein the evaluation unit comprises a second squaring unit for squaring the second frequency-filtered channel signal in order to acquire a second squared channel signal, wherein the evaluation unit additionally comprises a storage unit for storing the set of known data sequences, wherein the evaluation unit additionally comprises a first signal-to-noise distance determining unit in order to acquire, for each data sequence of the set of known data sequences, the first channel-specific signal-to-noise distance value of said data sequence of the set of known data sequences based on said data sequence of the set of known data sequences and based on the first squared channel signal, wherein the evaluation unit additionally comprises a second signal-to-noise distance determining unit in order to acquire, for each data sequence of the set of known data sequences, the second channel-specific signal-to-noise distance value of said data sequence of the set of known data sequences based on said data sequence of the set of known data sequences and based on the second squared channel signal, wherein the evaluation unit additionally comprises an argmax unit for determining a maximum signal-to-noise distance value, and wherein the evaluation unit additionally comprises a data sequence determining unit in order to select that data sequence of the set of known data sequences as the determined data sequence that has the maximum signal-to-noise distance value associated.

20. The device in accordance with claim 1 , wherein the device additionally comprises a channel estimate output unit, wherein the channel estimate output unit is configured to output the first channel-specific signal-to-noise distance value of the determined data sequence as a first channel estimate of a first channel, and wherein the channel estimate output unit is configured to output the second channel-specific signal-to-noise distance value of the determined data sequence as a second channel estimate of a second channel.

21. A device for recognizing a network address encoded by a frequency-modulated input signal, comprising: an interface unit for receiving the frequency-modulated input signal, and a device in accordance with claim 1 for determining a data sequence encoded by the frequency-modulated input signal which comprises a plurality of data elements, the encoded data sequence designating a network address, wherein the evaluation unit of the device in accordance with claim 1 is configured to determine a data sequence signal-to-noise distance value for each known data sequence of a set of known data sequences, wherein each known data sequence of the set of known data sequences designates a network address each.

22. A method for determining an encoded data sequence as a determined data sequence, the encoded data sequence being encoded by an input signal frequency-modulated in accordance with a modulation rule, the encoded data sequence comprising a plurality of data elements, comprising: filtering the frequency-modulated input signal in order to acquire a first frequency- filtered channel signal and a second frequency-filtered channel signal, determining, for each data sequence of a set of known data sequences, a first channel-specific signal-to-noise distance value of two channel-specific signal-to-noise distance values based on said data sequence and based on the first frequency-filtered channel signal, and associating said first channel-specific signal-to-noise distance value of the two-channel-specific distance values to said data sequence, determining, for each data sequence of the set of known data sequences, a second channel-specific signal-to-noise distance value of the two channel-specific signal-to-noise distance values based on said data sequence and based on the second frequency-filtered channel signal, and associating said second channel-specific signal-to-noise distance value of the two-channel-specific distance values to said data sequence, and selecting from the set of known data sequences a data sequence as the determined data sequence that has an associated channel-specific signal-to-noise distance value which is greater than another channel-specific signal-to-noise distance value associated to another one of the known data sequences.

23. A non-transitory computer-readable medium comprising a computer program for performing the method in accordance with claim 22 when the computer program is executed on a computer or signal processor.